Oral Thrush in Adults and Babies: Signs, Treatment and Prevention

Oral thrush, also called oral candidiasis, is an infection in the mouth caused by a yeast-like fungus called Candida. healthdirect Australia says around 1 in 2 people have Candida in their mouth without it causing a problem; thrush happens when the fungus grows more than usual.

What are the symptoms of oral thrush?

In adults

The NHS describes a mouth that is red inside with white patches. Wiping the patches off leaves red spots that can bleed. The NHS and healthdirect also list:

• cracks or sores at the corners of the mouth
• pain or burning in the mouth, such as a sore tongue or gums
• an unpleasant taste, or not tasting things properly
• red or smooth patches on the tongue, and sores under dentures (healthdirect)
• difficulty eating and drinking (NHS)

In babies

The NHS says a baby with oral thrush will have a white coating on their tongue that may look like cottage cheese and cannot be rubbed off easily, and sometimes white spots in the mouth. NHS breastfeeding guidance adds a white film on the lips, being unsettled when feeding and, in some babies, nappy rash that will not clear up. Pregnancy, Birth and Baby (an Australian government service) also mentions drooling. For other kinds of mouth sore, see mouth ulcers.

Who is more likely to get oral thrush?

The US Centers for Disease Control and Prevention (CDC) says thrush is uncommon in healthy adults, and the risk is highest in babies under 1 month old. Pregnancy, Birth and Baby says newborns are more prone because their immune systems are still maturing, and premature babies even more so.

The CDC, NHS and healthdirect list other things that make thrush more likely:

• Dentures. The NHS advises not wearing them at night, or wearing ones that do not fit. See looking after your mouth in older age.
• Antibiotics, especially over a long time (NHS).
• Steroid inhalers (inhaled corticosteroids) for asthma. The Australian Dental Association says the risk is higher with regular high doses.
• A dry mouth, for example from medicines such as antihistamines. See dry mouth.
• Diabetes, cancer and HIV (CDC), and chemotherapy (NHS). The CDC says a weakened immune system raises the risk. See diabetes and oral health.
• Smoking or vaping (CDC, healthdirect). See smoking, vaping and oral health.
• Older age, poor oral hygiene and nutritional deficiencies (healthdirect).

Is oral thrush contagious?

The sources put this differently. The NHS says oral thrush in adults is not contagious, and the CDC says candidiasis does not spread between people. Pregnancy, Birth and Baby says the Candida yeast is contagious and can pass through an infected child's saliva, and both it and NHS breastfeeding guidance say thrush can pass back and forth between a breastfeeding mother and baby.

How is oral thrush treated?

healthdirect says a doctor can usually diagnose thrush by looking in your mouth, and may take a swab if the diagnosis is unclear or treatment is not working. The Australian Dental Association says a swab sent to a laboratory is needed to diagnose it.

Thrush is treated with antifungal medicines. The CDC says most mild to moderate infections are treated with an antifungal gel in the mouth for 7 to 14 days, using medicines such as clotrimazole, miconazole or nystatin, and more severe infections with tablets, most commonly fluconazole. healthdirect mentions lozenges and, in some cases, tablets from a doctor, usually for 1 to 4 weeks or until you have had no symptoms for 7 days.

Where to get treatment differs by country:

• UK: the NHS says a pharmacist can sell a mouth gel suitable for adults, children and babies over 4 months. See a GP for a baby under 4 months.
• Australia: healthdirect says to see your doctor if you think you have oral thrush, but many treatments are sold in pharmacies without a prescription, and if you have had thrush before you can talk to your pharmacist.

Cautions from the sources:

• Miconazole gel and warfarin. The UK medicines regulator (MHRA) says people taking warfarin, a blood thinner, should not use over-the-counter miconazole oral gel, because bleeding has been reported. Tell the pharmacist about any other medicines you take.
• Nystatin liquid. The NHS says to hold it in your mouth for 30 seconds if possible, and to keep taking it for 2 days after the thrush clears.
• Steroid inhalers. The NHS says to keep using your inhaler while you treat the thrush.
• Babies. Pregnancy, Birth and Baby says to put gel on a young baby's tongue and gums with a clean finger, not a spoon or dropper, which could be a choking risk, and to wash your hands afterwards. It says you should see an improvement within 1 to 2 days.

healthdirect says complications are rare, but can include the infection spreading to the food pipe (oesophagus) or elsewhere in the body, and liver problems from some antifungal medicines.

Breastfeeding and thrush

Thrush can affect a breastfeeding mother's nipples. The NHS lists burning nipple pain (especially after feeds), itchy or sensitive nipples, flaky or shiny skin on the nipple or areola (the darker skin around it), and white patches, tiny blisters or loss of colour there. Pregnancy, Birth and Baby says there are often no obvious signs, and that pain at every feed is more likely to be about how your baby is attached.

Pregnancy, Birth and Baby says you and your baby both need treatment at the same time, so you do not pass it back and forth. A doctor may prescribe an antifungal cream for your nipples after each feed, or tablets, which it says are safe while breastfeeding. Always tell the doctor you are breastfeeding. It says symptoms should improve within 2 to 3 days; go back if there is no improvement after 5 days.

You can keep breastfeeding. The NHS says if it is too painful, express your milk instead. Advice on stored milk differs: Pregnancy, Birth and Baby says not to freeze expressed milk to use later because thrush may come back, while the NHS says there is currently no evidence that this happens.

To stop thrush spreading, both suggest washing your hands well (especially after nappy changes), using separate towels, changing breast pads often, washing bras and towels in hot water, and sterilising dummies, bottle teats and toys.

How can you prevent oral thrush?

The NHS, healthdirect and the Australian Dental Association suggest:

• Brush your teeth twice a day. With no teeth, brush your gums and tongue with a soft toothbrush (NHS).
• Clean dentures, take them out at night, and keep having dental check-ups.
• Rinse your mouth after eating or taking medicine (NHS).
• After a steroid inhaler, rinse your mouth with water or brush your teeth (NHS, healthdirect). The Australian Dental Association differs on brushing: it says to rinse with water or a fluoride mouthwash and to wait at least 60 minutes before brushing. It also suggests using a spacer device.
• Do not smoke or vape.
• With a long-term condition such as diabetes, go to your regular check-ups (NHS).
• For babies, sterilise bottles after each use and dummies regularly (NHS).

healthdirect also suggests avoiding antiseptic mouthwashes, which can upset the balance of bacteria in the mouth and let Candida grow (see mouthwash: do you need it?), and cutting down on sugar. Pregnancy, Birth and Baby, however, says there is little evidence that reducing sugar or yeast in your diet stops thrush.

Frequently asked questions

Sources

1. Oral thrush (mouth thrush), NHS, accessed September 2026
2. Thrush (breastfeeding challenges), NHS Best Start in Life, accessed September 2026
3. How and when to take or use nystatin, NHS, accessed September 2026
4. Side effects of budesonide inhalers, NHS, accessed September 2026
5. Miconazole: over-the-counter oral gel contraindicated in patients taking warfarin, Medicines and Healthcare products Regulatory Agency (Drug Safety Update), accessed September 2026
6. Oral thrush, healthdirect Australia, accessed September 2026
7. Oral thrush in babies and children, Pregnancy, Birth and Baby (Australia), accessed September 2026
8. Nipple thrush, Pregnancy, Birth and Baby (Australia), accessed September 2026
9. Asthma and oral health, Australian Dental Association, accessed September 2026
10. Risk factors for candidiasis, US Centers for Disease Control and Prevention, accessed September 2026
11. Treatment of candidiasis, US Centers for Disease Control and Prevention, accessed September 2026

This article is general information about oral health. It is not a diagnosis or a substitute for advice from a dentist or doctor who knows your situation. If you have pain, swelling, bleeding that does not settle, or a problem that is getting worse, see a dental professional. In an emergency, contact your local emergency service.

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